Ahhhh, how I have missed the classic ADHD too much attention to detail questions of the bodybuilding forums.
Well first red flag is you said your on and off. Before you start buying supplements why dont you work on consistency. Once you get consistency, then we can talk about the basics of nutrition and food. Once you get food down pat, you will already be 10lbs heavier and will have to spend your leftover money on more food.
Oh, and get rid of p90x.